Editing Scientific visualization (section)

== Topics ==
[[File:PET-MIPS-anim.gif|thumb|right|[[Maximum intensity projection]] (MIP) of a whole body [[PET scan]].]]
[[File:InnerSolarSystem-en.png|thumb|[[Solar System]] image of the main asteroid belt and the Trojan asteroids.]]
[[File:2006-01-14 Surface waves.jpg|thumb|right|Scientific visualization of Fluid Flow: [[Surface waves]] in [[water]]]]
[[File:FIRST measurement of SF6 and NH3.jpg|thumb|[[Chemical imaging]] of a simultaneous release of SF<sub>6</sub> and NH<sub>3</sub>.]]
[[File:AFMimageRoughGlass20x20.png|thumb|right|Topographic scan of a glass surface by an [[Atomic force microscope]].]]

=== Computer animation ===
[[Computer animation]] is the art, technique, and science of creating moving images via the use of [[computer]]s. It is becoming more common to be created by means of [[3D computer graphics]], though [[2D computer graphics]] are still widely used for stylistic, low bandwidth, and faster [[real-time rendering]] needs. Sometimes the target of the animation is the computer itself, but sometimes the target is another [[Recording medium|medium]], such as [[film]]. It is also referred to as CGI ([[Computer-generated imagery]] or computer-generated imaging), especially when used in films. Applications include [[medical animation]], which is most commonly utilized as an instructional tool for medical professionals or their patients.

===Computer simulation===
[[Computer simulation]] is a computer program, or network of computers, that attempts to [[simulation|simulate]] an abstract [[model (abstract)|model]] of a particular system. Computer simulations have become a useful part of [[mathematical model]]ling of many natural systems in physics, and computational physics, chemistry and biology; human systems in economics, psychology, and social science; and in the process of engineering and new technology, to gain insight into the operation of those systems, or to observe their behavior.<ref>
Steven Strogatz (2007). "The End of Insight". In: ''What is your dangerous idea?'' John Brockman (ed). HarperCollins.</ref> The simultaneous visualization and simulation of a system is called [[visulation]].

Computer simulations vary from computer programs that run a few minutes, to network-based groups of computers running for hours, to ongoing simulations that run for months. The scale of events being simulated by computer simulations has far exceeded anything possible (or perhaps even imaginable) using the traditional paper-and-pencil [[mathematical modeling]]: over 10 years ago, a desert-battle simulation, of one force invading another, involved the modeling of 66,239 tanks, trucks and other vehicles on simulated terrain around [[Kuwait]], using multiple supercomputers in the [[United States Department of Defense|DoD]] [[High Performance Computing Modernization Program]].<ref name="JPLsim">[http://www.jpl.nasa.gov/releases/97/military.html "Researchers stage largest military simulation ever"]. (news), [[Jet Propulsion Laboratory]], [[Caltech]], December 1997.</ref>

=== Information visualization ===
[[Information visualization]] is the study of "the [[Visual system|visual]] [[Representation (arts)|representation]] of large-scale collections of non-numerical information, such as files and lines of code in [[software system]]s, [[library]] and bibliographic [[database]]s, networks of relations on the [[internet]], and so forth".<ref name="MF08"/>

Information visualization focused on the creation of approaches for conveying abstract information in intuitive ways. Visual representations and interaction techniques take advantage of the human eye's broad bandwidth pathway into the mind to allow users to see, explore, and understand large amounts of information at once.<ref>James J. Thomas and Kristin A. Cook (Ed.) (2005). [http://nvac.pnl.gov/agenda.stm ''Illuminating the Path: The R&D Agenda for Visual Analytics''] {{webarchive|url=https://web.archive.org/web/20080929155753/http://nvac.pnl.gov/agenda.stm |date=2008-09-29 }}. National Visualization and Analytics Center. p.30</ref> The key difference between scientific visualization and information visualization is that information visualization is often applied to data that is not generated by scientific inquiry. Some examples are graphical representations of data for business, government, news and social media.

===Interface technology and perception===
[[Human-computer interaction|Interface technology]] and [[perception]] shows how new interfaces and a better understanding of underlying perceptual issues create new opportunities for the scientific visualization community.<ref name="LR94">[[Lawrence J. Rosenblum]] (ed.) (1994). ''Scientific Visualization: Advances and challenges''. Academic Press.</ref>

=== Surface rendering ===
[[Rendering (computer graphics)|Rendering]] is the process of generating an image from a [[3D model|model]], by means of computer programs. The model is a description of three-dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, [[texture mapping|texture]], [[lighting]], and [[shading]] information. The image is a [[digital image]] or [[raster graphics]] [[image]]. The term may be by analogy with an "artist's rendering" of a scene. 'Rendering' is also used to describe the process of calculating effects in a video editing file to produce final video output. Important rendering techniques are:

;[[Scanline rendering]] and rasterisation
: A high-level representation of an image necessarily contains elements in a different domain from pixels. These elements are referred to as primitives. In a schematic drawing, for instance, line segments and curves might be primitives. In a graphical user interface, windows and buttons might be the primitives. In 3D rendering, triangles and polygons in space might be primitives.

;Ray casting
: [[Ray casting]] is primarily used for realtime simulations, such as those used in 3D computer games and cartoon animations, where detail is not important, or where it is more efficient to manually fake the details in order to obtain better performance in the computational stage. This is usually the case when a large number of frames need to be animated. The resulting surfaces have a characteristic 'flat' appearance when no additional tricks are used, as if objects in the scene were all painted with matte finish.

;Radiosity
:[[Radiosity (computer graphics)|Radiosity]], also known as Global Illumination, is a method that attempts to simulate the way in which directly illuminated surfaces act as indirect light sources that illuminate other surfaces. This produces more realistic shading and seems to better capture the '[[available light|ambience]]' of an indoor scene. A classic example is the way that shadows 'hug' the corners of rooms.

;Ray tracing
:[[Ray tracing (graphics)|Ray tracing]] is an extension of the same technique developed in scanline rendering and ray casting. Like those, it handles complicated objects well, and the objects may be described mathematically. Unlike scanline and casting, ray tracing is almost always a Monte Carlo technique, that is one based on averaging a number of randomly generated samples from a model.

=== Volume rendering ===
[[Volume rendering]] is a technique used to display a 2D projection of a 3D discretely [[Sampling (signal processing)|sampled]] [[data set]]. A typical 3D data set is a group of 2D slice images acquired by a [[computed axial tomography|CT]] or [[magnetic resonance imaging|MRI]] scanner. Usually these are acquired in a regular pattern (e.g., one slice every millimeter) and usually have a regular number of image [[pixel]]s in a regular pattern. This is an example of a regular volumetric grid, with each volume element, or [[voxel]] represented by a single value that is obtained by sampling the immediate area surrounding the voxel.

=== Volume visualization ===
According to [[Lawrence J. Rosenblum|Rosenblum]] (1994) "volume visualization examines a set of techniques that allows viewing an object without mathematically representing the other surface. Initially used in [[medical imaging]], volume visualization has become an essential technique for many sciences, portraying phenomena become an essential technique such as clouds, water flows, and molecular and biological structure. Many volume visualization algorithms are computationally expensive and demand large data storage. Advances in hardware and software are generalizing volume visualization as well as real time performances".

Developments of web-based technologies, and in-browser rendering have allowed of simple volumetric presentation of a cuboid with a changing frame of reference to show volume, mass and density data.<ref name="LR94"/>